Device in a system operating with CAN-protocol and in a control and/or supervision system

ABSTRACT

A control supervision system incorporates a digital serial communication and modules that are mutually communicable to this and operate with CAN-protocol. A control desk can be wirelessly connected to one or more modules operating with a signal protocol which does not take into account arbitration and/or confirmation functions appearing in the CAN-system. A particular receiving communication part executes the conversion of the signal protocol to the signal protocol of the CAN-system. A device for controlling a function in a first module in a CAN-system via a wireless connection to a second module in the system is provided. A system of mutually separate units, where each unit operates with a CAN-signalling protocol, intercommunicating with an identification system in which a key allocation between the units is based upon identities that are assigned by a module in the unit or a master system is also provided.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application is a divisional of U.S. patent application Ser.No. 09/101,748, filed Jul. 17, 1998.

BACKGROUND

The present invention relates to a device in a machine-control systemand/or process-supervision system operating with the Controller AreaNetwork” (“CAN”)-protocol according to standard ISO 11898. CAN-systemsof this type comprise modules which are intercommunicable via a digitalserial communication and in which a control and/or supervisory functioncan be realized from a first module or from a unit, which iscommunicable with the CAN-system, belonging to one or more secondmodule(s).

The present invention relates to a device in a machine-control system orprocess-control system. The said system has in the present case beenreferred to as a CAN-system, since the systems in question are requiredto use the signal protocol according to CAN (Controller Area Network,corresponding to standard ISO 11898). The invention in this case relatesto those types of CAN-system comprising modules which are connectablevia a digital serial communication and in which a function in a firstmodule is intended to be able to be observed, stimulated or registeredat a location for the placement of the first module. Reference is alsomade to Swedish patent application “Device in a system operating withCAN-protocol”, which was submitted on the same day by the same applicantand inventor.

It is previously known to be able to control machinery and equipment atcontrol desks which are connected via fixed connections or wirelessconnections. These proposals make use of the general control andsupervision principles. With reference to control desk arrangementsproposed with CAN-protocol, the arrangements in question are primarilythose with wire connections. Reference is also made to U.S. Pat. No.5,392,454.

With machine-control and process-control systems of this category, it ispreviously known that it is necessary to supervise the aggregates servedby the modules such that in fault-searching, system design, etc., it ispossible to establish whether the equipment controlled by a particularmodule is behaving as expected. It can be stated in this context that itmay be necessary to monitor the functions at valves, thermometers, etc.,so that in certain functional states it can be seen or registeredwhether the components in question are actually performing theirexpected function. It is also known to utilize machine-control systemsand process-control systems in which the equipment parts are connectedvia relatively long digital serial communications. The connection canalso be established at locations and sites where accessibility islimited.

In the radio-controlling of machines operating with CAN-protocol,problems arise from the fact that the protocol calls for arbitration andconfirmation functions which are extremely time-critical. In order toensure that the modules do not misinterpret a particular message inquestion, in certain cases the receipt of a one over the connection mustresult, for example, in a zero being immediately presented to preventdisturbances occurring within the system. This calls for sending andreceiving to be effected simultaneously by one and the same module,which, in turn, calls for a full duplex connection and timesynchronization between the sending and receiving channel in each moduleand predetermined maximum wave propagation time within the system. Thisis difficult to achieve in a radio system when such a system is oftenchosen to enable the distance between the modules within a system whichare connected by radio link to be easily varied. Radiocommunication istherefore less suitable for systems using the CAN-protocol. The objectof the present invention is to solve these problems.

In certain contexts, it is vital to be able to make use of repetitionfunctions linked to machines or machinery stocks operating withCAN-protocol. At places which are difficult to survey or difficult toaccess, there is a need to build up an existing CAN-system and introducea repetition function over difficult stretches or to create on atemporary or longer term basis two separately working CAN-systemsinstead of one. In this context, there is a need to be able tofacilitate system developments and system applications. The object ofthe invention is to solve these problems also.

There is also a need to achieve effective coordination ofmachine-controls in machinery stocks, e.g. in weaving sheds in whichweaving machines have hitherto been controlled individually and providedwith their own man-machine interface such as control desks. There is awish to be able to introduce CAN-protocol into the control of machinesof this category, this having been hindered by the above-specifiedproblems. The object of the present invention is to solve these problemsalso and it is proposed, in respect of this category of machinery-stockcontrol, that the controls be effected via radiocommunication from andto a common man-machine interface, such as a control unit or controldesk. The control equipment, is thereby simplified and a coordinated,effective control is able to be established in terms of service andproduction via or in the machinery stock.

Radiocommunication is often utilized between an operator's control unitand the control system of the machine which he controls. Examples ofsuch systems are radio-controlled airplanes, radio-controlledcontracting machinery, radio-controlled hoisting cranes, etc. of varioustypes. One problem is here to set up a radio channel which isexclusively between control unit and machine, such that the connectionis not disturbed by other operator/machine connections. The object ofthe present invention is to solve this problem also.

The invention also allows reduced susceptibility to theft and offershigh security within the system per se.

There is a great need to be able to carry out fault searches and testson modules which are situated at a distance apart and in which afunctional effect upon a first module is wanted to be able to befollowed at a second module, and vice versa. For instance, there is adesire in certain situations to initiate controls at a master in theCAN-system in order to obtain manifestations at one or more slavemodules. There is here a need to see whether the function is beingcorrectly performed by the components or aggregates controlled by themodule in question.

There is also a need to be able to stimulate a component or aggregate ata module and to discover what repercussions this has.

There is also a need to be able to carry out registration operations ina fault-searching and testing context for a certain period, as well asto acquire direct visual and signal information at the site for themodule subjected to testing or fault-searching.

The above must be practicable even if the modules are far apart andhidden from each other. Preferably, the above will be able to beeffected via an already existing switching function, i.e. connectionsand disconnections do not need to be made in each separate case/inrespect of each module.

SUMMARY

The invention aims to solve the whole or parts of the above problems.

What primarily can be considered to be characteristic of a deviceaccording to the invention is that it comprises two or morecommunication parts which form part of the CAN-system, respectivelybetween the CAN-system and the unit mentioned in the introduction, andwhich are communicable via one or more wireless connections, that when atransmission is made from a first communication part to a secondcommunication part, the parts operate with a signal protocol which takesno account of arbitration and/or confirmation function(s) found in theCAN-system. A particular receiving communication part executes orassists in the conversion of the said signal protocol to the signalprotocol of the CAN-system.

In one embodiment, the communication parts can be coupled to theCAN-system, which in the non-connected or non-activated state of thecommunication parts forms a unitary system and which in the connected oractivated state of the communication parts form two CAN-systems whichoperate separately relative to each other.

A particular pair of communication parts can in this case operate with aprotocol which is distinct from the CAN-protocol and is better suitedfor radiocommunication, e.g. Aloha, Ethernet, the WaveRaider protocolfrom GEC Plessey in England, etc. In one embodiment, the invention isutilized in respect of a machinery stock. As an example of a machinerystock can be cited weaving machines which are installed in one or moreweaving sheds and are respectively allocated one or more modules. Inthis case, the unit can comprise a service unit common to a number ofweaving machines, preferably the majority or all of the total number ofweaving machines. This service unit can comprise or contain a personalcomputer (PC).

In the case of weaving machines in a weaving shed, one or more modulesassigned to a weaving machine are connected to a service function in theweaving shed. This service function can consist of beam-changing,bobbin-changing, etc. Service staff receive information in parallel witha service machine which is appropriately connected to the particularweaving machine. Function information can therefore appear both on theunit and in control apparatus belonging to the service machine, thefunction measure or instruction in question being able to be preparedsimultaneously or in perfect coordination between the service machineand the staff involved. An effective synthesis is obtained forproduction and service measures which are necessary to the weavingmachines in order to maintain effective production. The machines can becoupled together in a control network in which a particular machine hasits own unique code and control system in order to prevent disturbancesbetween the machines. The frequencies are preferably chosen within thebroad-band range, i.e. 1 GHz or above, preferably the open Industrial,Scientific, and Medical (“ISM”) band, but infrared (“IR”) frequenciesand ultrasound frequencies can also be used. The latter particularly inrespect of acoustic communication in an underwater environment.

The device according to the invention also relates to a system ofmutually separate units which are intercommunicable by means ofradiocommunications, these being able to be set up such that messagechannels can be realized between two or more of the said units. Theradio communications operate here with an identification system in whicha key allocation can be realized, which in a particular connectioninstance enables messages to be transferred between selected units only.The particular unit is further designed with a CAN-system (ControllerArea Network), in which activations, control operations, functions,stimulations, readings, etc. in modules making up the unit areintercommunicable via a digital serial connection. The latter device isprincipally characterized by the fact that in each connection instancethe key allocation between the units is based upon anidentity/identities which, during a connection process for theconnection in question, are acquired from a module in the CAN-systemconcerned and/or from a master system or master control centre. Furtherfeatures of the devices in question can be derived from the followingpatent claims.

What primarily can be considered to be characteristic of a deviceaccording to the invention, comprising the module mentioned in theintroduction, is that a radiocommunication apparatus is arranged forconnection with a part belonging to a second module in the system forthe establishment of a radiocommunication channel between the locationfor the placement of the first module and a location for the placementof the second module. At the location for the placement of the firstmodule, radiocommunication equipment can be activated for initiation viaa radio channel and the said part of the radiocommunication equipment byactivation of a signal in the second module. This signal activationcauses the first module to perform its particular control and/orsupervisory function which then becomes able to be observed orregistered in place of the first module.

In one embodiment, the CAN-system forms part of a machine-control systemand/or process-control system in which a first signal exchange accordingto the CAN-protocol obtains between involved modules within the systemfor the control operation and the performance of the process. A firstactivation of the radiocommunication equipment at the first locationhereupon gives rise to a second activation of circuits in the secondmodule. This second activation induces the said signal activation in thesecond module.

In a further embodiment, the signal activation caused by the secondactivation gives rise to message initiation in the second module, whichprepares to dispatch a message via the module's communication circuit,over the connection to the first module. The second module is hereuponable to transmit the thus generated message, with a predetermined orderof priority, in the ordinary message or signal exchange between themodules. In one embodiment, the second module can cause interruption tothe ordinary message or signal exchange in the CAN-system. That signalactivation in the second module which is herein initiated by the secondactivation takes over the CAN-system for the generation and sending ofone or more test messages via the communication circuit and theconnection to the first module.

When its signal is activated on the basis of the second activation inthe second module, the second module can imitate a control orsupervisory function which can normally be found in the machine and/orprocess-control system. Alternatively, or as a supplement thereto, acontrol and/or supervisory function which is especially cut out for thetesting function is generated.

The radiocommunication equipment preferably operates two-way (half orfull duplex). This makes it possible for a stimulation of control orsupervisory component(s) or equipment at the first module to produce afeedback to the second module, via the connection to the second module.The latter generates a stimulation-responding information signal, whichis fed back to the radio equipment part situated at the first module.Information which is transferred via the radiocommunication equipmentcan thereby be indicated or presented on or at the saidradiocommunication equipment part at the first module.

In one embodiment, the radiocommunication equipment part at the firstmodule is connected to the control and or supervisory equipment servedby the first module and/or directly to the module.

In one embodiment, the second module is arranged such that it is merelya so-called “gateway” between the radiocommunication of the first unitand the CAN-system, i.e. a message from the first module via radio tothe second module is converted there to a CAN-message and transmitted onthe bus, and vice versa.

Further characteristics derive from the following patent claims and thedescription. The device also therefore works in cases where theequipment in the first module is stimulated, for example, manually,which stimulation can be monitored at the control orinformation-supplying unit to ascertain whether there are faults in theequipment and/or the communications.

Radiocommunication between control units and machines in machinerystocks can be economically established even where the machines operatewith CAN-protocol. Repetition functions can be inserted into theCAN-system or the machine and/or process-control system, which meansthat connections can be established for even poorly accessiblelocations. Proven methods are in fact able to be used in connection withthe radiocommunication control operation, as regards control desks,frequency usage, security arrangements, coding, keys, etc.

The above makes it possible for testing and function-checking to beeasily carried out on CAN-modules, using simulated control operationsand stimulations which are introduced to second modules at a distancefrom the first modules. The checks can be executed even if theconnecting line is long, e.g. 800 m, or the modules are hidden from oneanother. The stimulations can also be carried out on the visuallysupervised module or its equipment/components and the reactions to suchstimulations can be obtained in a second direction within the CAN-systemand recorded at the location for the first module(s).

DESCRIPTION OF THE FIGURES

A currently proposed embodiment of a device exhibiting thecharacteristics which are indicative of the invention shall be describedbelow with simultaneous reference to the appended drawings, in which:

FIG. 1 shows radiocommunication between a unit and a CAN-system

FIG. 2 shows how a CAN-system with repetition function can be dividedinto two CAN-systems,

FIG. 3 shows how a CAN-system can be arranged with a control unit whichcan work either directly connected to the CAN-bus and then utilize powerfrom this system or via a radio channel and then be powered from achargeable battery,

FIG. 4 shows transmitting and receiving units via a radio channel in aradiocommunication system, in which transmission takes place in aprotocol distinct from the CAN-protocol and in which conversion to theCAN-protocol is realized on the receiver side, and

FIG. 5 shows a simple system in which an operator control module whichworks on the CAN-bus is easily modified from a wire-bound system to aradio-controlled system,

FIG. 6 shows a device which enables a CAN-message to be converted to aradio message, and vice versa,

FIG. 7 shows diagrammatically how protocol exchange takes place betweenthe CAN-protocol and a radio protocol,

FIG. 8 shows a radiocommunication control system in respect of amachinery stock, e.g. in the form of weaving looms in a weaving shed,

FIG. 9 shows an arrangement for weaving machines in a weaving shed, inwhich information goes out to a service car in parallel with a controlpanel,

FIGS. 10 a and 10 b illustrate a simple way of setting up a secureradiocommunication between a control member and a machine in the examplearrangement of FIG. 9. FIG. 10 a checks whether the unit 1001 is of theright type and whether the individual is authorized to control themachine 1003. FIG. 10 b illustrates the CAN-connection 1002 beingdisconnected and communication being made via radio, showing that theradio units 1001 and 1003R have been exchanged for the compatible units1011 and 1010 after communication has been established.

FIG. 11 shows a construction site with radio-controlled cranes and theestablishment of a radio connection between these and a particularoperator.

FIG. 12 represents a basic and block diagram of a CAN-system in whichradiocommunication equipment parts are arranged at first and secondmodules in the system and in which the radiocommunication equipment hasbeen connected to the second module in order to simulate stimulationstherein, the effect of which upon the system can be monitored at thefirst module,

FIG. 13 shows in basic representation an antenna system for longtransfer distances in respect of equipment according to FIG. 1,

FIG. 14 shows in block diagram form the structure of the module 4Aaccording to FIG. 1, and

FIG. 15 shows in diagrammatic form the framework structure for digitalsignals which are used.

DETAILED DESCRIPTION

FIG. 1 shows in basic representation a CAN-system 101. By this is meanta machine-control and/or machine-supervision system. Alternatively, aprocess-control or process-supervision system can be obtained. TheCAN-system is represented by a number of modules 102, 103, 104, whichserve their parts of the system in question. Also included are a controlunit 105 and a radio module unit 106 connectable and connected to orforming part of the module 117. The said modules can intercommunicatevia a digital serial communication connection 107. FIG. 1 also shows acontrol desk function 108 comprising operating levers 109 and 110 and apersonal computer 111 with possible display unit 112. The unit 108further comprises a module 113, which can be synthesized with themodules on the bus via a radiocommunication system comprising a part114, and possibly also an adjustment unit 118, in the unit 108 and thesaid radio module 106. The radio module 106 and the part 114 cancomprise transmitter and receiver, so that a two-way communication 115,116 is obtained. Communication takes place via established radiochannels in the radiocommunication equipment and the latter operatespreferably in the broad-band range, see above. The units 116 and 114 areprovided with antennae 106 a and 114 a for the said communicationfacility. The modules 102, 103, 104 can in this case represent modulesforming part of machines in a machinery stock in which a particularmachine can operate with a number of modules. There is therefore apossibility of accomplishing controls from the unit 108 of the modulesin question via the CAN-system. The said machines in the said machinerystock can consist of weaving machines—described in greater detailbelow—installed in a weaving shed or of hoisting cranes within aconstruction area.

FIG. 2 shows how a CAN-system 201 having a repetition function can bearranged to form two different CAN-systems 202 and 203, the respectiveCAN-system here being equipped with radio modules, which can comprisetransmitter and receiver in accordance with the equipment 106, 117according to FIG. 1. The radio modules have been given the designation204 and 205 respectively. The first CAN-system has the modules 206, 207,208, 209 and the second CAN-system has the modules 210, 211, 212.Control functions can be performed via the modules 210, 211 and 212, viathe pilot pins 213, 214 and a personal computer 215. If the radiomodules 204 and 205 are uncoupled, then the CAN-buses 216 and 217 of thesub-systems can be joined together to form a common CAN-bus 218 in whichthe junction point has been denoted by A. In the case of separatecoupling and jump coupling, the CAN-bus ends would naturally have to becorrectly terminated and a power supply suitably arranged. Except forcertain accruing delays to the message, the divided system will functionas if it were coupled together without any changes in the system'ssoftware.

FIG. 3 shows a further variant of a CAN-system 301 with modules 302,303, 304 and 305. Here too, radio modules 306 and 307 are utilized. Theradio module 306 is tied to the CAN-system 301, whilst the radio module307 is assignable to a further CAN-system 308, which can be connected intwo alternative ways to the CAN-system 301. The one way is realized viaa mechanical, galvanically separated or wireless connection 309 or viathe radio modules 306 and 307, which operate in a manner correspondingto the radio modules according to FIGS. 1 and 2. The CAN-system 308 isprovided with three modules 310, 311 and 312 for the inputting andreceipt of information which is relevant to the system in connectionwith control and/or supervision within the system. In this case, abattery system 313 is utilized to power the CAN-system 308. When thesystem 308 is used at a distance from the system 301 and the radioconnection is utilized, then power is supplied from the battery system313. When the systems are coupled together, then the battery system 313is connected directly up to the power unit 315 of the CAN-system 301 viathe inductive connection 314 and the battery system is then able tocharge its integral accumulators. The CAN-system 301 is coupled togetherwith 308 by the connection 309 via an inductive coupling 316. A systemcan thereby be coupled together or separately coupled to form twosub-systems without mechanical connectors having pins and sockets, whichoften cause problems when exposed to wear and tear, corrosion andphysical damage. In many cases, one and the same control unit canoperate either conventionally “fixed” mounted and connected to theCAN-network or as a remote control unit. In the fixed position thebatteries are loaded. Whenever the unit is then wanted to be used as aremote control unit, it is simply disconnected from the, system. In thefixed-coupled position, the radio units have agreed on all parameterswhich are required for wireless communication. An advantage is also thatthe operating unit is able to be removed from the controlled unit andwithout a control unit the machine is difficult to steal.

FIG. 4 shows a monitoring/control unit 401, having one or more CPU's402, memories 403, a CPU-integrated or free-standing CAN-Controller 404(for example Intel 527A), a CAN-driver 405 (for example Philips 251A),communication adjustment circuits 406, etc., diagrammaticallyillustrated, built for the CAN-protocol, which are connectable to aradio unit 408 and also connectable to a CAN-connection 407. The radiounit 408 comprises two communication parts, a radiocommunication part409 having hardware and software, which enables a wireless communicationto be set up between different radio units, and a part having hardwareand software, incorporating one or more CPU's 410, memories 411,communication adjustment circuits 412, etc., diagrammaticallyillustrated, which allows communication with the unit 401. Examples ofsuch radio units are WaveRider from GEC (GB) and examples of a CAN-unitare CANnonBall and mini-CB from KVASER AB (SE). The radio part 408 andthe CAN-part 401 have at least one CPU each and can intercommunicate viaa serial or parallel interface 413. The parts 401 and 408 can be builttogether in a common casing 414 or each in its own casing, indicated by415, and can be connected by a connector 416. An advantage of having theradio unit 408 and the CAN-unit 401 mounted each in its own casing isthat the radio unit can be easily exchanged in the event of a fault,replaced by a similar radio unit in order to satisfy national orregional radiocommunication regulations, or can alternatively operatewith some other wireless communication based, for example, uponinfra-red or visible light, ultrasound, etc. The CAN-part can in thiscase be a standard unit with a parallel or serial output which allowsconnection to a unit equivalent to 408. Each radio part has a uniqueidentity, in the case of WaveRider an Ethernet address, and eachCAN-unit has a unique identity, for example an European Article Number(EAN) including a serial number. Each unit which will be able to becontrolled also has a unique identity, for example an EAN including aserial number.

The radio unit operates independently as regards radiocommunication andhas a network protocol for this. All radio units can intercommunicatewithin radio range on a common channel. Two or more radio units can beallocated or can themselves set up a channel which is exclusive to them.If further differentiation of the radio traffic is required, then two ormore radio units can establish an exclusive message channel within achannel by the messages being encoded with their own common key. Eachstation can be allocated a station name constituted, for example, by abinary code or an ASCII-file. By having two separate identificationsystems, one for radiocommunication and one for CAN-communication, avery secure and flexile communication system can be established in whichthe system, apart from being a communication system, can also be used todistribute and check the authority of operators to operate machines.

U.S. Pat. No. 5,392,454 describes how two radio units can set up acommon exclusive communication channel by first seeking contact witheach other via another type of communication channel and by thereexchanging information about each other's unique identity. By markingits messages with its identity during ordinary communication, aparticular unit can thus filter out those messages which are intendedfor the unit in question. The fact that the identification of themessage is based upon the identity of the radio unit represents a majordrawback, firstly in respect of the exchange of radio units and secondlyif multicast-type connections are wanted to be set up. The consequenceof the solution proposed in patent U.S. Pat. No. 5,392,454 is that theradio connection is tied between the transmitting and receiving radiounit and not between operator unit and machine or between machinesub-system and machine sub-system. The radio communication system can beregarded as the master machine-control system. The radiocommunicationunits are regarded as special units within the system.

In CAN-systems, for example those operating with CAN ELP (Higher LayerProtocol) “CAN Kingdom”, it is usual firstly for each node or module inthe system to have its own unique identity, which is based, for example,on an EAN and a serial number, and secondly for there to be a module ornode constituting a system node in the machine system. The identity ofthis node can also be used as identity for the machine. In the presentinvention, the radiocommunication unit is regarded as a CAN-node ofwhichever type, equating, for example, to a valve unit or a joystickunit. The radiocommunication system is thus regarded as the subordinatemachine-control system. When the system is started up or as soon as aradio unit is connected to the system, the system node can detect this,for example by a method described in CAN Kingdom. Depending upon thesituation, the system node can assign to the radio unit a general publicnetwork key or a unique key. A simple way of constructing a unique keyis to base this upon the identity of some node incorporated in thesystem, since all of them have a unique identity, inclusive of thesystem node itself. If, for some reason, a node other than the identityof the system node is chosen as basis for the exclusive network key,then this is entirely possible, at least in systems based upon CANKingdom, with maintained system security, since the system node is awareof all integral nodes and no node can be exchanged and work within thesystem without the consent of the system node. From a securityviewpoint, it is vital that it is the system node of that sub-systemwhich is critical to security within the total system which determinesthe network key and possibly also provides a jump plan or alternativelya dispersion code, depending upon whether a jumping frequency or spreadspectrum technique has been chosen. Examples of a suitable radioemploying the latter technique is the “2.45 Spread Spectrum Transceiver”from CRL Instrumentation in England. For example, in a system comprisinga hoisting crane and a remote control unit, it is the system node in thehoisting crane which has to assign the common network key to aparticular radio unit, not any of the radio units or the system node inthe remote control unit. Alternatively, network keys can be distributedat a still higher level within the system. For example, a unit which iscommon to a construction area can distribute network keys via a commonchannel to remote control units and cranes. The area-common unit thenhas complete information on all cranes and the identities of remotecontrol units within the area. It is vital that the radiocommunicationunits should be at a low level systematically within the machine systemand hence fully exchangeable without security risk. The problemsassociated with radio transmission, such as, for example, jump plan,jumping frequency, dispersion code, identification of radio transmitterand receiver, distribution of station identities, etc. can be solvedwholly within the radio system range and the machine system constructorneeds only to ensure an adequate network key distribution. Ahierarchically structured machine system includes an organization forthe generation and distribution of network keys and an organized way ofidentifying individual modules and groups of modules. The radio systemincludes an organization for the generation and distribution ofcommunication channels and an organized identification of individualsand also possibly groups of radio stations. The fact that the machinesystem distributes the network keys and has scope to acquire and employinformation on the identities of stations forming part of the radiosystem means that radiocommunication in a CAN-system can be usedsecurely. The identity of the station in the radio network can beexchanged by the system node for the identity of the system node, inwhich case the system ceases to form part of the original radio network.

Having CAN-modules whose only tasks are to constitute units for wirelesscommunication, hereinafter referred to as WCANM, is a major advantage inCAN-systems. An example: We have two wireless units, WCANM1 and WCANM2.In stage one we couple them together via the CAN-connection and theyperform the start-up process and can subsequently intercommunicate in asecure manner. In a system which is traditionally constructed, then itis now possible to remove a unit, for example a control lever andmonitoring unit, and replace this with a WCANM1. The removed module isnow coupled together with WCANM2 and we have a wireless connectionbetween the monitoring/control unit and the rest of the system. In itssimplest form, WCANM1 will now receive all messages on the CAN-bus. Asand when a message is correctly received, it is repackaged into aWCANN-message [sic] and sent to WCANM2, which unpacks the message andconverts it into a CAN-message and sends it to the monitoring/controlmodule. This module cannot distinguish between a message which hasundergone these conversions and a message which has arrived directly onthe CAN-bus, if the CAN-Identifier is the same. When thecontrol/monitoring module sends a message, the reverse takes place.WCANM2 receives the message, repackages it, transmits it to WCANM1,which repackages and sends out the message on the CAN-bus.

FIG. 5 illustrates a process according to the above. A CAN-systemcomprises a CAN-bus 500, to which the modules 501, 502, 503, 504 and 505are connected. The module 505 is a control module to which the controllevers 508 and 509 are connected and with which the control command canbe given to 501 and 502 or 503 and 504 respectively. By decoupling themodule 505 from the CAN-bus 500 and instead connecting up the radiomodule 511 and connecting the radio module 510 to the CAN-bus instead ofthe module 500, a wireless connection has been obtained between thecontrol module and the CAN-bus.

Below and in FIG. 6, a detailed account is given of how a CAN-message isconverted into a radio message and vice versa. A message is created bythe CPU 602 in module 601 and transferred to its CAN-Controller 604 fordispatch. Apart from data, the CPU sends information on theCAN-Identifier to which the data is to be coupled, on whether thisidentifier is of the standard or extended type, on the fact that it is adata message and not a so-called “remote request” and on the number ofbytes which the data occupy in the data field. The CAN-Controllerconverts this information into a bit pattern according to theCAN-protocol, in which, inter alia, a CRC check code for the message isworked out, and transmits the bit pattern 701 (in FIG. 7) on the CAN-bus600 according to the rules of the CAN-protocol via the CAN-driver 605.Once the CAN-Controller 607 of the WCANM-module 606 has correctlyreceived the message, then information corresponding to the CPU inmodule 601 is downloaded to its CAN-Controller (604) so as to beaccessible to the CPU 608 of the WCANM-module. This reads the receivedinformation and packages it into a data format which is common toWCANM-modules:

Bytes 0–3 CAN-Identifier Byte 4 Data Length Code Bytes 5–12 Data Field20

Note here that a CAN-Identifier is only a bit pattern and that thearbitration characteristic associated with this part of a messageaccording to the CAN-protocol is of no importance to the radiotransmission and that the Cyclical Redundancy Checking (“CRC”) code andacknowledgement bit are not transferred. The data string 702, in FIG. 7,according to the above is transmitted to the CPU 610 of the radio unit609A via a local serial or parallel bus 611 for sending. (The interface611 can comprise eight leads for data, six leads for handshaking, threein each direction, and a feedback signal lead for initiating the radioat the start-up of the system). The CPU 610 then deposits the datastring as data according to the protocol used by the radio units amongstthemselves 703. Here the data are treated as whichever data and the CPU610 is not therefore required to have any information on theCAN-protocol. The radio message having been transmitted, the CPU in theradio unit of a receiving WCANM-module, following receipt according tothe radio protocol, uses the local bus to transmit the received datastring 704 to the CPU of its module's CAN-part. The CPU of the CAN-partthen creates a CAN-message 705 in accordance with the format of the datastring and presents this to its CAN-Controller for dispatch on theCAN-bus and the process continues in the customary CAN manner. TheCAN-Controller calculates a new CRC check code and presents a one in theacknowledgement slot, since it is transmitter of a message which is newto this part of the system.

In CAN-systems constructed with CAN Higher Layer Protocol “CAN Kingdom”,an application in a module is tied together with a CAN-Identifier via aso-called “Folder” to allow the data exchange between applications indifferent modules to be coupled together. If the CAN-system isconstructed according to CAN Kingdom, the Folder number can be usedinstead of the CAN-Identifier in the format of the data string 702 andthe Data Length Code omitted:

Byte 0 Folder Number Byte 1 - n Data n = 0 ... 8

Other necessary information derives from the particular “Folder Label”in accordance with the CAN Kingdom protocol. The length of theether-borne message is thereby reduced. Furthermore, differentCAN-Identifiers can be used for the very same message in the varioussub-systems. This can be an advantage, since the priority of the messagecan then be adjusted to the conditions in the particular sub-system. Insystems developed for radiocommunication, only messages necessary to aparticular receiver are sent via radio and each subsystem has aninternal flow of messages between its nodes.

In CAN-systems it often happens that modules are set to receive onlycertain messages. This is generally done by filtering out certain bitpatterns in the arbitration field of the CAN-protocol, which inspecification ISO 11898 is known as the Identifier Field. Since, from aCAN viewpoint, WCANM-modules can be quite ordinary CAN-modules, thesealso have the scope to filter out messages on the bus. If it is knownwhich messages are to be received on both sides of the wirelesscommunication, then WCANM1 and WCANM2 respectively can be set to filterout those messages which are to be received on the respective other sideand thereby reduce the load on the wireless connection. Since there isno known method of satisfying the time demands which are placed upon theacknowledgement bit of the CAN-protocol via a wireless connection with ahigh bit speed, typically 125 kb/s to 1 Mb/s, over longer distances,typically from a few meters up to five hundred meters, the wirelesscommunication is not bit-synchronous with the line-bound communication.Since the CAN-protocol is not followed in ether transmission, this canoften be done faster and with different scheduling of the messagetransmissions. If standard circuits for CAN are used, then it may beexpedient to take the message as it appears in the normal receptionbuffer which is read by the CPU, i.e. with CAN ID field, control fieldand data field, but without start bit, stuff bits, CRC bits, etc., andto transmit this according to a protocol suitable for wirelesscommunication. Another alternative is to receive from the CAN-bus entirebit streams and to buffer these as far as the acknowledgement bit. Whenthis is read to zero on the CAN-bus, the packet is transmitted via theether and, following receipt, the bit stream is transmitted on theCAN-bus on the reception side. From the acknowledgement bit onwards, thereceiving WCANM-module itself creates remaining bits according to theCAN-protocol. If, during this period, the first WCANM-module reads anerror frame after the acknowledgement bit during the remaining part ofthe CAN-message, then an error code is immediately transmitted to thereceiving WCANM-module, which then sends out an error frame on itsCAN-bus. This is an effective way of sending CAN-messages, since CAN'serror controls are utilized (and therefore no error control is requiredin the ether protocol) and there are few bits needing to be transmitted.The problem remains however, when some bit is incorrectly received fromthe ether or, worse still, a CAN-error arises on the CAN-bus belongingto the receiving side. It can then be too late for the receivingWCANM-module to send an error message over the ether. The originalmessage can already have been accepted on the sending side. This problemcan be solved in the CAN Higher Layer Protocol.

A further way of compressing the message which can be utilized,especially when the ether communication is operating at high bit speed,is for the bits of the CAN-message on the sending side to be received upto the point where the CRC-code and the stuff bits are removed, sincethese are not involved in the working-out of the CRC-code by the CANerror protocol. This packet is transmitted via-the ether and, if theCRC-code is correct on arrival, then a CAN-bus is recreated.

The communication between WCANM-modules [sic] can be of the full duplexor half duplex type. Full duplex offers the fastest transfer, since, ifthe receiver detects an error, it can immediately send back an errormessage to the transmitter. In the case of half duplex, the receiverwould have to wait until the whole message is sent before a reply can begiven. Radio networks are most commonly of the half duplex type. Atypical sequence is as follows:

Transmitter Receiver 1. Set up connection. 2. Acknowledgement 3. Sendsmessage 4. Acknowledgement 5. Disconnect the connection

A more effective procedure is to send short messages constantly to andfro between the transceivers. A CAN-message is always short incomparison to necessary information in a radio network protocol for the2.4 GHz band (the ISM band), in the order of magnitude of 11 to 154 bitsdepending upon the way in which the information is packed in the radioprotocol. It is therefore expedient for the CAN-information to beincluded in the “Establishment of connection” message and theacknowledgement message, thereby providing an effective use of thechannel. The fact that a short message is “ping-ponged” in this waymeans that a system-supervising node in the CAN-system has the chance tohave continuous information stating that the radio connection is intactand functioning. A broad-band communication further requires that theclock in a particular transceiver module shall in some way besynchronized with a real or virtual system clock. A constant exchange ofshort messages between stations in the system allows good precision tobe maintained in the system's clocks, thereby enabling the creation ofan effective broad-band protocol built on jumping frequency orbit-pattern synthesis and enabling the clock of the radio system also tobe used as a system clock within the CAN-system.

An ever increasing number of modern weaving looms are constructed with aCAN-system. Each weaving loom has a display, a key set and very oftenalso a memory card reader. These devices are utilized only when a personoperates them, i.e. for the vast majority of the time they are totallyredundant items of equipment. It is usual for one person to haveresponsibility for twenty or so weaving machines. Often all weavingmachines are connected to a network having a supervisory function andthe person in charge acquires information telling him which machine togo to in order to carry out some form of service. By connectingWCANM-modules to each weaving machine and a WCANM-module to a portableunit suitable for passing and taking information from a person, aso-called “Man Machine Interface (MMI), for example a portable personalcomputer, a number of advantages are attained. All displays, key setsand memory card readers can be removed. When the person stands at themachine, he connects his MMI to the CAN-network in the manner previouslydescribed. Since only one MMI is required per person, this can beconsiderably more powerfully designed than if there were one to eachmachine. Data files which were previously transferred using memory cardscan now be transmitted from the MMI. Fault analysis programs, graphicpresentation, tuning tool programs, etc. can be incorporated in the MMIand keyboards, mouse, etc. can be made user-friendly and upgraded moreregularly than the machines. Communication with the person often drawson greater computer resources than the machine-control function, so thatthe machine-control function can be made cheaper, more secure and moreeffective in that these functions are taken over by the MMI.

When the operator is not directly connected to a machine, he isconnected to the wireless network. As soon as a machine requires actionon the part of the operator, the machine sends out a message on thewireless network. The operator brings up on his display a list of allweaving machines which have requested assistance and for what reason. Ifmore than one machine has requested assistance, the operator can choosethe order in which he shall attend to the machines and he is alsoprepared for what has to be done so that he has suitable tools with him.

FIG. 8 shows a diagrammatic representation of a device according to theabove. Each weaving machine 801, 802, 803, 804, 805, 806, and 807 isequipped with radio modules 801 a, 802 a, etc. and has in each case aninternal CAN-control system which can communicate with the radio module.The operator has a PC 808 to which a radio unit 808 a is connected. Whenthe operator is supervising the plant, all radio units operate on thesame channel and information can be exchanged between the PC and allweaving machines. When the operator is working on a weaving machine, thePC and the weaving machine use an exclusive channel, directcommunication with the weaving machine 801 being illustrated in thefigure. A further advantage is that the wireless network can replace thecurrently wire-bound network for production data to and from themachines and for supervision thereof.

The automation of a factory often incorporates various types ofdriverless trucks and similar equipment which also have an internalCAN-control system. These can also be connected up to the wirelesssystem. FIG. 9 shows a diagrammatic representation of a small part ofsuch a system with a weaving machine 902, a driverless truck carrying areplacement beam 904 and an operator unit 903. If, for example, a warpbeam is to be replaced, then a message 901A reporting this can pass fromthe weaving machine 902 both to the operator 903 and to the unit 904transporting replacement beams. This, in turn, can send a message 905Ato the operator about its status. When the operator arrives at themachine, the driverless truck with the replacement beam is alreadythere. In the event of further automation, the fixed machine interactsautomatically with the moving machine and the operator is summoned onlyif the machines, for some reason, have failed in their task.

FIGS. 10 a and 10 b show an example of the above process. Amonitoring/control unit 1001 equipped with a radio unit 1001R isconnected via a CAN-bus 1002 to a machine 1003 equipped with a radiounit 1003R. The system-supervising node 1004 of the machine detects thata monitoring/control unit 1001 is connected to the machine and asks thesystem node 1005 of the unit 1001 for the EAN and serial numbers of themonitoring/control unit and uses these to check whether the unit 1001 isof the right type and whether the individual is authorized to controlthe machine 1003. The method for carrying out such a check is, interalia, described in CAN Higher Layer Protocol “CAN Kingdom”. If anothermonitoring/control unit 1006 already has control over the machine, theconnected unit 1001 is denied further communication with the system inthe machine 1003. If no previous monitoring/control unit has control andtype and possibly also the new individual is authorized to control themachine, then the machine transmits a unique station name 1007, forexample the EAN, inclusive of serial number, of the unit 1001. Thisstation name is subsequently used jointly by the machine and themonitoring/control unit as identity for their communication channel. TheCAN-connection 1002 is disconnected and communication can be made viaradio as shown in FIG. 10 b. FIG. 10 b has revealed that the radio units1001R and 1003R have been exchanged for the compatible units 1011R and1010R after communication has been established. This is totally feasibleby virtue of the fact that a particular system node 1005 and 1004delivers the agreed channel code to the respective new radio units, oncethese have been connected to the respective CAN-network.

FIG. 11 shows a more complex process. A company has a number of cranes1101, 1102, 1103 at a work site. All cranes have a unique identity, 1 i,2 i, 3 i and are each equipped with a radio unit 1 r, 2 r, 3 r. Eachcrane operator 1104, 1105, 1106 has his own monitoring/control unit withradio. Each such monitoring/control unit has a unique identity, 4 i, 5 iand 6 i respectively. Whenever a crane does not have active connectionwith a control unit, it listens in on a channel 1107 which is common tothe work site. Whenever a crane, in this instance the crane 1102, isassigned to a crane operator, in this instance 1106, a central radiounit 1108 seeks contact with the assigned crane 1102, which isidentified by 2 i, and informs the crane operator 1106 of the identityof the monitoring/control unit, 6 i or alternatively the network keybased on 6 i. Once the crane operator is on the spot, he starts up hismonitoring/control unit. The crane unit seeks contact on the generalchannel with the selected monitoring/control unit 1006 having theidentity 6 i and when they have made contact with each other the cranereports its identity 2 i and the fact that it is master of theconnection. A connection is then set up on an exclusive channel 1109,i.e. the crane communicates how frequency jumping is to be done. Inbrief, it is therefore the case that cranes which do not have contactwith a selected control unit, in terms of radiocommunication, complywith the jumping frequency from a central unit. Once contact is obtainedwith a selected monitoring/control unit, the crane establishes contactwith this, leaves the central unit and assumes control over thegeneration of frequency jumping. The monitoring/control unit complieswith this. If the radio connection is of the “spread spectrum” type,then the dispersion code is given instead of the jump plan.

A plurality of control units can be assigned to one and the same crane.They then belong to the same network. In the working range of the crane,a particular monitoring/control unit is assigned to a part-region. Thepart-regions can be partially overlapping or the crane can follow apredetermined path between the part-regions. The crane is thereby ableto be reliably controlled at a number of sites. When the load entersinto a part-region, it obeys only that control unit which is responsiblefor the area. There are a number of ways of solving the allocation ofwho has control over the machine on a given occasion. A furtheralternative is that the machine, after a certain period in which nocontrol command is forthcoming, for example two seconds, accepts thatparticular transmitter, of those which are accepted, which first issuesthe control command. The machine then obeys this transmitter until suchtime as it has failed to give any control commands for a two secondperiod.

In systems, especially those which are constructed according to theprinciples contained in CAN Kingdom, in which a plurality of remotecontrol units are able to operate one and the same unit, controlcommands from a particular remote control are assigned to aCAN-Identifier by the system node of the controlled unit. The controlcommands are in this case first received by the system node, which, inturn, transmits control messages on the CAN-bus of the machine. Thesystem node can receive control commands from all remote control unitswhich communicate on the network key common to the machine and can thenselect which remote control unit's control commands will be implementedaccording to a set of rules, for example the work area within which theunit is situated or, quite simply, that the remote control unit whichfirst gives a shift command then retains control until it issues a codefor relinquishment of the control, is shut off or remains inactive for apredetermined period. Thereafter, the system node of the machine waitsfor a first best command from any of the authorized remote control unitsand then executes control commands only from this latter until theparticular remote control unit hands over control according to theabove.

In a number of machines, for example process machines, a large number ofmeasuring points and adjusting appliances are apparent, which aregeographically dispersed and on many occasions poorly accessible. Theoperator sits in a room in which he supervises and controls the entiresystem via VDU's. Whenever something is detected which calls foron-the-spot observation, a communication problem arises. For example, aclosed position of a valve is indicated, which should be open. When theoperator makes an on-the-spot visual inspection, he sees that the valveis open. Has it opened whilst he was on his way to the valve or is thevalve signaling a closed position despite the fact that it is open? Ifnow a WCANM-module [sic] is connected and he has a MMI as previouslydescribed, then he can read on the spot the message which the valve istransmitting on the CAN-bus and decide whether there is a fault with thevalve or not. The WCANM-module connected to the CAN-bus, from theviewpoint of the CAN-signal, can be in a totally passive mode, i.e. nottransmitting a single bit, not even an acknowledgement bit. It can alsohave a CAN-active mode, so that the operator from his MMI is able tocommand the valve to open or close so as to monitor its functioningthere on the spot. Of course, the control system for the process plantwould have to be made such that the operator's actions do not jeopardizethe security of the process.

FIG. 12 illustrates a machine-control and/or process-control system withits modules 1A, 2A, 3A and 4A, which are intercommunicable via a serialdigital connection 5A in a manner which is known per se. In order tosimplify representation, the designation “CAN-system” is applied to thissystem. According to the invention, the module serves aggregates formingpart of the said machine-control system and/or process-control system.In FIG. 12 a valve in the aggregate is indicated by 6A and a thermometerin the aggregate by 7A. The length L of the connection 5A can berelatively long and can stretch over 200 m, for example. The modules andaggregates in the system can also be situated out of sight of eachother.

In systems of this category, there is a need to be able to initiate afault-searching, testing, control operation, etc. at the first module1A. Such fault-searching or equivalent can require that second modulesin the system need to be stimulated or need to establish signaltransmissions or signal receptions at certain stages of the fault-searchor equivalent. In order to save staff, a radiocommunication apparatus isused, comprising two radiocommunication equipment parts 8A and 9A. Thefirst part 8A can be independent from the CAN-system, whilst thecommunication part 9A is connected to or forms part of the secondmodule. The connection between the part 9A and the module 4A can hereinbe made via a connection 10A, which can consist of a physicalconnection, non-galvanic connection, wireless connection, etc. Themodule 4A can be temporarily or permanently connected to the CAN-bus.The radiocommunication equipment 8A, 9A operates, where appropriate,with two-way connections 11A, 12A. The communication equipment 8A, 9Acan in this case utilize one or more channels, with use preferably beingmade of radio channels in the broad-band range, i.e. in the range offrequencies above 1 GHz, for example the ISM-band. Theradiocommunication equipment part 8A is provided with a control panel13A, which can be of a type which is known per se. The panel isconnected to the transmitting and receiving unit 14A of the part 8A,which incidentally can be of identical type to 9A, via an adjusting unit15A. As a supplement thereto, the panel can be directly connected to theaggregate or components served by the first module 1A. This connectionis effected via a second adjustment unit 16A and the connection per seis symbolized by 17A.

An initiation i1 at the panel 13A induces an activation of thetransmitting part 14A, which, via a channel 11A, transmits theactivation to the radio receiver part 9A. This receipt gives rise to asignal generation i2 to the module 4A via an adjustment unit 23A. Themodule contains a microprocessor 18A, which causes a signal message 19Ato be generated, which is then transmitted to the connection 5A via thecommunication circuit 20A of the module 4A (see FIG. 1). Thetransmission can be made according to an order of priority which isdetermined by the CAN-protocol and in which the module, after admissionto the connection 5A, is able to transmit the message in question to thefirst module. Once the message 19A is received in the first module, afunctional stimulation of the component 6A, 7A or the equipment inquestion is realized, which functional stimulation is provoked by theinitiation i1 at the control panel. The control operation can in thiscase comprise a reversal of the valve 6A, a raising or lowering of thetemperature 7A, etc. The said reversal or temperature change can bevisible to an observer at the first module. Through stimulations of hiscontrol unit 13A, the observer is therefore able to obtain visualevidence of whether the control system in question is accomplishing whatit is meant to. At the control unit 13A, information 13A can also beobtained from the components or aggregate served by the module 1A. Bykeeping the radiocommunication equipment connected, registration andviewing can be carried out for shorter or longer periods of time.

Alternatively, a manual, electrical or other stimulation of thecomponents or of the aggregate served by the first module 1A caninitiate a message 21A generated in the first module, which message istransmitted to the second module 4A via the communication circuit 22A inthe first module and the connection 5A. The said signal message 21Ainduces a signal initiation i4 in the second module and activation ofthe transmitter part in the radiocommunication equipment part 9A. Via achannel 12A, the information in question is transmitted to the receivingpart in the radiocommunication part 14A and thereupon gives rise to thegeneration of an information signal is to the adjustment unit 15A, foronward conveyance to the control unit 13A or an information-supplyingunit at which the information is displayed or registered. A location orsite for the first module 1A is indicated by A, whilst a correspondinglocation or site for the module 4A is indicated by B. After the operatorhas carried out a check or fault-search at module 1A, he can proceed tomodule 3A, for example, and carry out equivalent work, providing thatthe module 4A is kept connected. He does not in this case need toconnect any equipment to the CAN-bus, but can continue to use theradiocommunication equipment 9A to transmit suitable messages andreceive chosen messages on the CAN-bus, via the still connected units 4Aand 9A. For communication over very long distances, up to a fewkilometers, it may be necessary to have directional receiving antennaein order to satisfy standards relating to maximum transmitted power.FIG. 13 shows such an arrangement for radiocommunication units ofpreviously described type, 24A and 25A, which are each equipped with anomnidirectional transmitter antenna 24 bA and 25 aA respectively and adirectional antenna 24 bA and 25 bA respectively. Other equipment inFIG. 1 is symbolized by 4A′ and 8A′.

FIG. 14 shows a diagrammatic representation of is a monitoring/controlunit 201A, having one or more CPU's 202A, memories 203A, aCPU-integrated or free-standing CAN-Controller 204A, a CAN-driver 205A,communication adjustment circuits 206A, etc.

The unit 201A is built for the CAN-protocol and is connectable firstlyto a radio unit 208A and secondly to a CAN-connection 207A. The radiounit 208A comprises two diagrammatically illustrated communicationparts, a radiocommunication part 209A having first hardware andsoftware, which enables a wireless communication to be set up betweendifferent radio units, and a second part having hardware and software,incorporating one or more CPU's 210A, memories 211A, communicationadjustment circuits 212A, etc., which allows communication with the unit201A. Examples of such radio units are WaveRider from GEC Plessey (GB)and examples of a CAN-unit are CANnonBall and mini-CB from KVASER AB(SE). The present invention can be implemented using these standardunits. The radio part 208A and the CAN-part 201A have at least one CPUeach and can intercommunicate via a serial or parallel interface 213A.The parts 201A and 208A can be built together in a common casing or, asin FIG. 5, can be applied each in its own casing 214A and 215A, and canbe mutually connected by a connector 216A. An advantage of having theradio unit 208A and the CAN-unit 201A mounted each in its own casing isthat the radio unit can be easily exchanged in the event of fault andreplaced by a similar radio unit in order to satisfy national orregional radiocommunication regulations The CAN-part can in this case bea standard unit with a parallel or serial output which allows connectionto a unit equivalent to 208A. If WaveRider is chosen as the radio part,the interface 213A will consist of eight lines for data, a so-called“data bus”, six lines for handshaking (three in each direction) and oneline for a feedback signal for initiating the radio when the system isstarted up. Each radio part has a unique identity, in the case ofWaveRider an Ethernet address, and each CAN-unit has a unique identity,for example an EAN including a serial number. Each unit which will beable to be controlled also has a unique identity, for example an EANincluding a serial number.

Data transfer of an eight-bit byte from the CPU 202A to the CPU 210A iseffected such that 202A activates an interruption signal to 210A, whichresponds with an acknowledgement signal indicating that it is ready toreceive data. (Otherwise a signal is activated which signifies “tryagain once more”). 202A presents a byte on the data bus and activatesthe signal “data are accessible”. 210A reads the byte, acknowledges thetransfer and stores it away in the memory 211A. This is repeated untilall of the byte is transferred. Transfer from 210A to 202A is carriedout in reverse.

FIG. 15 describes a detailed illustrative embodiment of signaling from amodule corresponding to the panel 13A according to FIG. 12, generationof a message and the shaping of the message and its insertion on the busand reception in a module corresponding to 1A. FIG. 15 shows only anoperator unit 301A connected to a communication unit 302A via aCAN-interface 303A and a communication unit 304A and a valve withcontrol electronics 305A connected to a CAN-bus 306A. Other modulesconnected to 306A are not depicted, but the total system corresponds tothat shown in FIG. 1. Both the units 302A and 304A each constitute acomplete radio unit corresponding to the whole of the device in FIG. 2,i.e. the radio unit can send and receive a message both via a CAN-busand via the ether. A modulation command to the valve 305A is generatedfrom the operator unit 301A and is transferred as a CAN-message 307A tothe CAN-Controller of the communication unit, which forwards the data308A to the CPU in the CAN-part. This creates a message 309A formattedfor the radio part. 309A is described in detail by 310A, which has thefollowing byte sequence: an overhead block with the parts 321A and 322A,in which 321A comprises two bytes 311A which indicate the number ofbytes making up the message inclusive of 311A, a two-byte sequentialnumber 312A (for suppression of subsequent multiply transmitted radiomessages) and a six-byte long destination address 313A, a six-byte longconsignor address 314A, two bytes 315A indicating the number of bytes ofuser data 316A to follow, and the part 322A made up of two or threebytes 317A which conclude the string. The user data 316A are the same as308A. The CPU in the radio part takes charge of the arrived string andconverts it into a radio message 318A with a necessary overhead 319A—forsetting up and synchronizing the radio transfer—and 320A for concludingthe sequence and ensuring it was correct in terms of the CRC checktotal, etc. The radio overhead incorporates the information 321A and322A. The radio module in the communication unit 304A receives thestring 318A and recreates the string 310A, this being transferred to theCPU of the CAN-unit, which extracts 323A and creates the information forthe CAN-Controller, which then, in turn, presents the CAN-message 324Aon the CAN-connection 306A. The valve unit 305A now receives the commandvia the CAN-connection and implements the same, which can be verified bythe operator.

The invention is not limited to the embodiment shown by way of exampleabove, but can be subject to modifications within the framework of thesubsequent patent claims and the inventive concept.

1. A testing device in a CAN-system including a digital serialcommunication bus and having a group of first modules connected to saiddigital serial communication bus at different locations (A) forcontrolling equipment at each location (A), the testing devicecomprising: a second module connected to said digital serialcommunication bus at a location (B), spaced from said locations (A),said second module including a radio communication means and means forgenerating an activation message in a complete CAN message format inresponse to a received message which has a partial CAN message formatretaining substantially all of the CAN message format, wherein saidpartial CAN message signals one of said first modules over said digitalserial connection; and a portable control unit having a radiocommunication means for establishing a radio communication link withsaid second module, and for generating commands for activating saidequipment at each of said locations (A), said portable control unithaving an interface means for generating a partial CAN messagerepresenting said commands and having a substantially CAN messageformat, said portable control unit transferring said partial CAN messagevia said radio communication link to said second module, said secondmodule generating said complete CAN message responsive to said partialCAN message and forwarding said complete CAN message via said serialcommunication connection to said first group of modules, wherein saidcommands are capable of being observed at each of said locations (A) inresponse to said complete CAN message.
 2. A device according to claim 1,wherein the CAN-system produces a first signal between the first modulesto perform the particular process of the control system, and a firstactivation of the portable control unit at the first location gives riseto activation of circuits in the second module, generating the signalactivation in the second module to produce said first signal.
 3. Adevice according to claim 2, wherein the signal activation initiates amessage in the second module for transmission over the digital serialcommunication connection to the first modules.
 4. Device according toclaim 1, wherein the second module transmits a message over said serialcommunication connection according to a predetermined order of priorityin the ordinary exchange of messages between the first modules.
 5. Adevice according to claim 4, wherein the second module causes aninterruption in the ordinary exchange of messages or signals within theCAN-system, and the signal activation in the second module controlsgeneration and dispatch of one or more test messages via a communicationcircuit to the first modules.
 6. A device according to claim 5, whereinthe second module, when a signal is activated imitates a control orsupervisory function, which normally occurs in the CAN system andgenerates a supervisory control operation for a testing orfault-searching function.
 7. A device according to claim 1, wherein theradiocommunication means operates with two-way connections such that astimulation of a controlled or supervised component at a first moduleproduces a feedback from the first module via the digital serialconnection to the second module, whereby an information signalrepresenting the stimulation is generated and transferred via theradiocommunication means to the portable control unit at the firstmodule location.
 8. A device according to claim 7, wherein theinformation in said messages makes it possible for a user to evaluatesaid control of said component.
 9. A device according to claim 8,wherein the control of said component induces a signal emission via afixed connection established between the first module means and aninformation-supplying unit at one of said locations A, and in that theinformation and signal-emission can be compared at theinformation-supplying unit in order to discover any defectiveness in thecommunication path via the serial communication, the second module andthe radiocommunication channel.
 10. A device according to claim 1,wherein the operation of equipment connected to said first modules areobservable.
 11. A device according to claim 1, wherein theradiocommunication means operates at frequencies of 2.4 GHz or higher.12. A device according to claim 1, wherein the radiocommunication meanspart at the first module location is connected to a control orsupervisory equipment part served by the first module.
 13. A testingdevice in a CAN-system connected by a digital serial communication bus,the testing device comprising: a first group of module means connectedto said digital serial communication bus at a first group of locations(A), respective ones of said first group of module means being connectedto control equipment at each of said location; a second module meansconnected to said digital serial communication bus at a second location(B), and having a radio communication interface means for creatingpartial CAN messages which retain a substantially CAN message formatfrom complete CAN messages on said digital serial communications bus;and portable radio communication means for linking each location of saidfirst group of locations (A) to said second module at location (B),whereby complete CAN messages from said first module means relating tothe connection of said equipment are sent via said digital serialcommunication bus to said second module means and transferred as apartial CAN message via said radio link to said portable radiocommunication means.
 14. A testing device which permits testing at afirst plurality of locations of a CAN-system, the testing devicecomprising: a module at each of said first plurality of locations thatoperates connected equipment; a portable control panel connected to aradio communication terminal that is positioned at each of said firstplurality of locations for as to receive information related tofunctioning of said equipment; and a second module at a second location,said second module being configured to receive and create partial CANmessages which retain a substantially CAN message format from completeCAN messages on said CAN system, said CAN messages containinginformation relating to the operation of said connected equipment, saidsecond module including a radio communication terminal configured toforward said partial CAN messages to said control panel, wherein theinformation relating to operation of said equipment is monitored by saidcontrol panel at each of said first plurality of locations.
 15. Atesting device for verifying operations of a CAN-system comprising aplurality of modules interconnected on a serial digital communicationbus, wherein at least one of said modules at a first location hasequipment connected thereto, the testing device comprising: a controlpanel adapted to be moved from module to module, said control panelhaving a radio terminal that receives and transmits information; and asecond module connected to said digital communication bus at a secondlocation, said second module having a radio terminal configured toreceive partial CAN messages which retain a substantially CAN messageformat from said control panel, wherein said radio terminal establishesa complete CAN messages from said partial CAN messages and transfersinformation received from said serial digital communication bus as apartial CAN message to said control panel, wherein commands are issuedto said equipment from said control panel, and information generated bysaid equipment is monitored by said control panel.